US 2009/0026168 A2 describes a method for producing rigid-flexible circuit boards having a flexible circuit board with an interposed base layer, which is arranged between two layers with electrical circuits. The two layers are laminated with the copper circuits by a protective layer, onto which in turn a dielectric layer is laminated, onto which in turn a copper foil is laminated. A rigid circuit board structure is formed between two rigid parts, which are flexibly connected to one another by the dielectric layer having predetermined openings. In a first cutting process, the dielectric material is removed at an interface between a lying region and the rigid part by formation of a first groove, while exposing part of the copper foil. In a second cutting process, a second groove is cut in, laterally offset from the first groove, and the opposite copper layer is exposed. This is followed by an etching process, in order to remove the exposed copper foil at the bottom of the first groove, thereby creating a second groove, which is in connection with the previously formed opening. The rigid structure that still remains is removed in the bending region.
This method is very laborious and, apart from the cutting out of partial layers by means of a laser beam, envisages the use of etching chemicals and possibly mechanical cutting tools.